Hard disk drive incorporating rotating magnetic disks is commonly used for storing data in the magnetic media formed on the disk surfaces, and a movable read/write transducer is then used to read data from or write to the tracks on the disk surfaces.
As consumers constantly desiring greater storage capacity for such disk drive devices, as well as faster and more accurate reading and writing operations, different methods are used to improve the recording density of information recording disk drive unit. As track density increases, it becomes more and more difficult to quickly and accurately position the read/write transducer over the desired information tracks on the disk. Thus, disk drive manufacturers are constantly seeking ways to improve the positional control of the read/write transducer in order to take advantage of the continual increases in track density.
One approach that has been effectively used by disk drive manufacturers to improve the positional control of read/write transducer for higher density disks is to employ a slider and micro-actuator assembly. FIG. 1 provides an illustration of a typical disk drive unit with a slider. The disk drive device 100 has magnetic hard disks 101, a typical drive arm 104 with a HGA 105 mounted thereon, a spindling voice-coil motor 108 (VCM) for controlling the motion of the drive arm 104, and a spindle motor 102 for spinning the disks 101. The HGA 105 includes a slider 103 with a read/write transducer (not shown) embedded therein and a suspension to support the slider 103. When the disk drive operates, the spindle motor 102 will rotate the disk 101 at a high speed, and the slider 103 will fly above the disk 101 due to the air pressure drawn by the rotated disk 101. The slider 103 moves across the surface of the disk 101 in the radius direction under the control of the VCM 108. With a different track, the slider 103 can read data from or write data to the disk 101.
FIGS. 2a-2b show that the slider 103 has a piezoelectric (PZT) element 22 buried in the back side of the floating type slider 103. The slider 103 has a leading edge and a trailing edge opposite the leading edge, a read/write transducer 21 formed at the trailing edge, a PZT element 22 sandwiched between the read/write transducer 21 and the slider body. The PZT element 22 has two electrodes 23 coupling with the PZT layer 25. As illustrated in FIG. 2b, when the slider 103 flies above the disk, the PZT element 22 will deform according to the input voltage, as indicated to a displacement direction 24a of the PZT element 22 which cause a displacement direction 24b of the read/write transducer 21. Thus the position of the read/write transducer 21 can be adjusted.
Another approach that has been used to improve the positional control of read/write transducer is following. As disclosed in U.S. Pat. No. 6,928,722, FIGS. 3a-3b show a slider 203 including a substrate 11, two electrodes layer 15a, 15b attached on the substrate 11, a PZT element 141 sandwiched between the electrodes layer 15a, 15b, and a read/write transducer 12 located on the side of the PZT element 141. Referring to FIG. 3b, when a voltage is applied to the electrode layers 15a and 15b, the PZT element 141 is driven and enables to deform, which accordingly adjusts the position of the read/write transducer 12.
However, as the PZT elements 22 and 141 are located adjacent to the read/write transducer in above-mentioned two approaches, the driving of the PZT elements will produce electrical charge and generate a potential voltage, which will make the read/write transducer damaged in case that, for example, ESD (electrical static discharge damage) problem happens. And the deformation of the PZT elements are not only in head track direction but also in head fly height direction, which means when adjusting the read/write transducer for the position of the head track, the deformation will affect the head flying height performance, thus decreasing the dynamic performance of the slider.
Hence, it is desired to provide an improved HGA and a suspension thereof, and a disk drive with the same to overcome the above-mentioned drawbacks.